Method of controlling a monitoring operation of physical downlink channel in wireless communication system

ABSTRACT

The present invention relates to a wireless communication system and a terminal providing a wireless communication service and to a method by which a base station and a terminal transmit and receive data in an evolved universal mobile telecommunications system evolved from universal mobile telecommunications system or a long term evolution system, and more particularly, to a method of controlling a monitoring operation of a physical downlink channel during a radio resource allocation procedure such that the radio resource allocation procedure can be performed with a minimum power usage by the terminal.

CROSS REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. §119, this application claims the benefit ofearlier filing date and right of priority to Korean Application No.10-2010-0060834, filed on Jun. 25, 2010, and U.S. ProvisionalApplication Ser. Nos. 61/239,796, filed on Sep. 4, 2009, and 61/242,397,filed on Sep. 15, 2009, the contents of which are incorporated byreference herein in their entirety.

TECHNICAL FIELD

The present invention relates to a wireless communication system and amobile terminal providing a wireless communication service and to amethod by which a base station and a mobile terminal transmit andreceive data in an evolved universal mobile telecommunications system(E-UMTS) evolved from universal mobile telecommunications system (UMTS)or a long term evolution (LTE) system, and more particularly, to amethod of controlling a monitoring operation of a physical downlinkchannel, thereby minimizing a power consumption of the mobile terminal.

BACKGROUND ART

FIG. 1 shows a network structure of the E-UMTS, a mobile communicationsystem, applicable to the related art and the present invention. TheE-UMTS system has been evolved from the UMTS system, for which the3^(rd) Generation Partnership Program (3GPP) is proceeding with thepreparation of the basic specifications. The E-UMTS system may beclassified as the LTE system.

The E-UMTS network may be divided into an evolved-UMTS terrestrial radioaccess network (E-UTRAN) and a core network (CN). The E-UTRAN includes aterminal (referred to as User Equipment (UE), hereinafter), a basestation (referred to as an eNode B, hereinafter), a serving gateway(S-GW) located at a termination of a network and connected to anexternal network, and a mobility management entity (MME) superintendingmobility of the UE. One or more cells may exist for a single eNode B.

FIGS. 2 and 3 illustrate a radio interface protocol architecture basedon a 3GPP radio access network specification between the UE and the basestation. The radio interface protocol has horizontal layers comprising aphysical layer, a data link layer, and a network layer, and has verticalplanes comprising a user plane for transmitting data information and acontrol plane for transmitting control signals (signaling). The protocollayers can be divided into the first layer (L1), the second layer (L2),and the third layer (L3) based on three lower layers of an open systeminterconnection (OSI) standard model widely known in communicationsystems.

The radio protocol control plane in FIG. 2 and each layer of the radioprotocol user plane in FIG. 3 will now be described.

The physical layer, namely, the first layer (L1), provides aninformation transfer service to an upper layer by using a physicalchannel. The physical layer is connected to an upper layer called amedium access control (MAC) layer via a transport channel, and data istransferred between the MAC layer and the physical layer via thetransport channel. Meanwhile, between different physical layers, namely,between a physical layer of a transmitting side and that of a receivingside, data is transferred via a physical channel.

The MAC layer of the second layer provides a service to a radio linkcontrol (RLC) layer, its upper layer, via a logical channel. An RLClayer of the second layer may support reliable data transmissions. APacket Data Convergence Protocol (PDCP) layer of the second layerperforms a header compression function to reduce the size of a header ofan Internet protocol (IP) packet including sizable unnecessary controlinformation, to thereby effectively transmit an IP packet such asInternet protocol version 4 (IPv4) or Internet protocol version 6 (IPv6)in a radio interface with a relatively small bandwidth.

A radio resource control (RRC) layer located at the lowest portion ofthe third layer is defined only in the control plane and handles thecontrolling of logical channels, transport channels and physicalchannels in relation to configuration, reconfiguration and release ofradio bearers (RBs). The radio bearer refers to a service provided bythe second layer (L2) for data transmission between the UE and the UMPSTerrestrial Radio Access Network (UTRAN).

According to a radio resource allocation request method in a relatedart, after requesting a radio resource allocation to a network, aterminal must continuously monitor a downlink channel until it receivesthe allocated radio resource. However, during a radio resourceallocation procedure, the terminal can not possibly receive the radioresource immediately after requesting the radio resource allocation.Therefore, an operation of continuously monitoring the downlink channelmay cause an unnecessary power consumption of the terminal.

DISCLOSURE OF THE INVENTION

Therefore, an object of the present invention is to minimize anunnecessary power consumption of a mobile terminal by controlling amonitoring operation of a physical downlink channel effectively.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein,there is provided a method of controlling a monitoring operation of aphysical downlink channel in wireless communication system, the methodcomprising: triggering a signaling in order to allocate at least oneradio resource for an uplink data transmission; determining whether thetriggered signaling is being transmitted to a network; and selectivelyperforming the monitoring operation of the physical downlink channelbased on the determining step.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 shows a network structure of an E-UMTS, a mobile communicationsystem, applicable to the related art and the present invention;

FIG. 2 shows an exemplary structure of a control plane of a radiointerface protocol between a UE and a UTRAN based on 3GPP radio accessnetwork standards according to the related art;

FIG. 3 shows an exemplary structure of a user plane of the radiointerface protocol between the UE and the UTRAN based on 3GPP radioaccess network standards according to the related art;

FIG. 4 illustrates a scheduling request (SR) procedure using adedicated-scheduling request (D-SR) channel;

FIG. 5 illustrates a radio resource allocation procedure aftertriggering of a buffer status report (BSR) and an SR; and

FIG. 6 illustrates a radio resource allocation procedure aftertriggering of a buffer status report and an SR according to anembodiment of the present invention.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

One aspect of this disclosure relates to the recognition by the presentinventors about the problems of the related art as described above, andfurther explained hereafter. Based upon this recognition, the featuresof this disclosure have been developed.

Although this disclosure is shown to be implemented in a mobilecommunication system, such as a UMTS developed under 3GPPspecifications, this disclosure may also be applied to othercommunication systems operating in conformity with different standardsand specifications.

Hereinafter, description of structures and operations of the preferredembodiments according to the present invention will be given withreference to the accompanying drawings.

In general, in the LTE system, in order to effectively use radioresources, the base station should know which and how many data eachuser wants to transmit. In case of downlink data, the downlink data istransferred from an access gateway to the base station. Thus, the basestation knows how many data should be transferred to each user throughdownlink. Meanwhile, in case of uplink data, if the UE does not directlyprovide the base station with information about data the UE wants totransmit to uplink, the base station cannot know how many uplink radioresources are required by each UE. Thus, in order for the base stationto appropriately allocate uplink radio resources to the UEs, each UEshould provide information required for the base station to scheduleradio resources to the base station.

To this end, when the UE has data to be transmitted, it providescorresponding information to the base station, and the base stationtransfers a resource allocation message to the UE based on the receivedinformation.

In this process, namely, when the UE informs the base station that ithas data to be transmitted, the UE informs the base station about theamount of data accumulated in its buffer. It is called a buffer statusreport (BSR).

The BSR is generated in the format of a MAC control element, included ina MAC protocol data unit (PDU), and transmitted from the UE to the basestation. Namely, uplink radio resources are required for the BSRtransmission, which means that uplink radio resource allocation requestinformation for BSR transmission should be sent. If there is allocateduplink radio resource when the BSR is generated, the UE would transmitthe BSR by using the uplink radio resource. The procedure of sending theBSR by the UE to the base station is called a BSR procedure. The BSRprocedure starts 1) when every buffer does not have data and data isnewly arrived to a buffer, 2) when data is arrived to a certain emptybuffer and a priority level of a logical channel related to the bufferis higher than a logical channel related to the buffer previously havingdata, and 3) when a cell is changed. In this respect, with the BSRprocedure triggered, when uplink radio resources are allocated, iftransmission of all the data of the buffer is possible via the radioresources but the radio resources are not sufficient to additionallyinclude the BSR, the UE cancels the triggered BSR procedure.

However, if there is no allocated uplink radio resource when the BSR isgenerated, the UE performs an SR procedure (i.e., resource allocationrequest procedure).

The SR procedure includes two methods: one is using a D-SR (DedicatedScheduling Request) channel set for a physical uplink control channel(PUCCH), and the other is using a random access channel (RACH) process.Namely, when the SR procedure is triggered and the D-SR channel has beenallocated, the UE sends a radio resource allocation request by using theD-SR channel, whereas if the D-SR channel has not been allocated, the UEstarts the RACH procedure. In case of using the D-SR channel, the UEtransmits a radio request allocation signal on uplink via the D-SRchannel. The SR procedure may be continuously performed until the UE isallocated uplink shared channel (UL-SCH) resources.

FIG. 4 illustrates a scheduling request (SR) procedure using adedicated-scheduling request (D-SR) channel.

As illustrated in the FIG. 4, a base station (e.g. eNB) may allocate aconfigured D-SR channel resource to a terminal (UE) periodically. If theterminal has data to be transmitted in an uplink direction and radioresource(s) have not been allocated to the terminal, the terminal maytransmit the data in the uplink direction by using the configured D-SRchannel resource. If the terminal does not have data to be transmitted,the terminal does not use the configured D-SR channel resource. Afterreceiving the D-SR channel from the terminal, the base station maydetermine a radio resource distribution according to a schedulingalgorithm, and may notify an amount of allocated uplink radio resourceto the terminal through a physical downlink control channel (PDCCH).

Hereafter, some concepts of discontinuous reception (DRX) will beexplained. The DRX refers to discontinuous reception and signifies theoperations about when (i.e. at when point in time) the base stationshould send information related to radio resource allocation to themobile station during the process of communication between the basestation and the mobile terminal.

Namely, a mobile terminal having to always monitor the downlink channel(e.g., PDCCH), would result in undesirable power consumption for themobile terminal. Thus, to resolve this issue, the mobile terminal andthe base station operate according to pre-established consistent rules,such that the base station sends radio resource allocation informationvia the PDCCH to the mobile terminal only at specific times. As aresult, the mobile terminal only needs to monitor the PDCCH at certainspecified times, which reduces power consumption thereof.

In general, the UE may be configured by the RRC with a DRX functionalitythat allows it to not continuously monitor the PDCCH. In the LTE system,the DRX functionality may consist of a Long DRX cycle, a DRX InactivityTimer, a DRX Retransmission Timer, and optionally a Short DRX Cycle anda DRX Short Cycle Timer.

Here, an Active Time will be explained. The active time may refer to aspecific time that the UE should wake up and monitor a downlink channel(e.g., PDCCH). Any other time except for the active time, the UE doesnot need to monitor the downlink channel.

The active time may include the following types of time periods:

1) a time during which an On-Duration timer, or a DRX Inactivity timer,or a DRX Retransmission timer, or a Contention Resolution timeroperates;

2) a time during which a Scheduling Request procedure is beingperformed;

3) a time during which a radio resource allocation message (forretransmissions) is sent, with respect to uplink transmissions;

4) a time during from after the RACH resource message (MSG-2) istransmitted up to the time when a cell radio network temporaryidentifier (C-RNTI) or a Temporary C-RNTI (that indicates the allocationof radio resources for an initial or new transmission) is received.

When a DRX cycle is configured, the UE shall perform the followingprocedures for each sub-frame (i.e., transmission time interval (TTI)):

if a short DRX cycle is used: start the On Duration Timer when[(SFN*10)+sub-frame number] modulo (current DRX Cycle)=DRX Start Offset;

if a hybrid automatic repeat request (HARQ) round trip time (RTT) Timerexpires in this sub-frame and the data in the soft buffer of thecorresponding HARQ process was not successfully decoded: start the DRXRetransmission Timer for the corresponding HARQ process;

if a DRX Command MAC control element is received: stop the On DurationTimer; stop the DRX Inactivity Timer;

if the DRX Inactivity Timer expires or a DRX Command MAC control elementis received in this sub-frame: if the short DRX cycle is configured: ifthe DRX Short Cycle Timer is not running, start the DRX Short CycleTimer; use the Short DRX Cycle, else: use the Long DRX cycle;

if the DRX Short Cycle Timer expires in this sub-frame: use the long DRXcycle;

during the Active Time, for a PDCCH-sub-frame except if the sub-frame isrequired for uplink transmission for half-duplex frequency-divisionduplex (FDD) UE operation: monitor the PDCCH;

if the PDCCH indicates a downlink (DL) transmission: start the HARQ RTTTimer for the corresponding HARQ process; stop the DRX RetransmissionTimer for the corresponding HARQ process;

if the PDCCH indicates a new transmission (uplink (UL) or DL): start orrestart the DRX Inactivity Timer.

if a DL assignment has been configured for this sub-frame and no PDCCHindicating a DL transmission was successfully decoded: start the HARQRTT Timer for the corresponding HARQ process.

A radio resource allocation request procedure will be explained. When aterminal (UE) request a radio resource allocation to a base stationthrough a D-SR channel, the terminal may continuously monitor a downlinkchannel until a completion of radio resource allocation. However, ingeneral, the terminal does not receive the radio resource immediatelyafter transmitting the radio resource allocation request.

In the FIG. 4, it takes approximately 7-8 ms from a time that theterminal (UE) uses a D-SR channel (time (1)) to a time that the UEactually receives a radio resource allocation (time (4)) with includinga signaling delay time and a base station's processing time.Accordingly, the terminal can not receive a radio resource allocationmessage from the base station (i.e., eNB) immediately after transmittingthe radio resource allocation request. However, in general, the terminalcontinuously monitors a downlink channel, and this cause an unnecessaryconsumption of the terminal's power.

FIG. 5 illustrates a radio resource allocation procedure aftertriggering of BSR and an SR.

As shown in the FIG. 5, the radio resource allocation procedure may bedivided into 4 different time period.

The first time period may refer to a time period from a time that aBSR/SR is triggered or pending to a first available time that SR can betransmitted on a PUCCH. In general, the first time period may be variedaccording to a setup of the radio resource(s) allocation of the PUCCHfor transmitting the SR request. In the FIG. 5, it is assumed that thePUCCH radio resource(s) are allocated at 0 ms, 20 ms, 40 ms. Here, ifthe SR is triggered at 2 ms, the terminal does not perform any operationfrom 2 ms to 20 ms, because the SR only can be actually transmitted tothe base station at 20 ms. However, in general, the terminalcontinuously monitors a downlink channel (e.g., PDCCH) during thisperiod, and such unnecessary monitoring operation of the terminal maycause unnecessary power consumption.

The second time period may refer to a time period from a time that theSR is transmitted to a first available time that the terminal canreceive a uplink grant (UL grant) message from a base station (e.g.,eNB). In general, the second time period may be related to anuplink/downlink RTT and/or a processing time by the base station.Accordingly, after transmitting the SR, there is some time delay thatthe terminal has to wait for receiving the radio resource allocationmessage. However, in general, the terminal also continuously monitorthis time period as well. Therefore, just like the first time period, anunnecessary power consumption of the terminal may be caused in thesecond time period as well.

The third time period may refer to a time period from the firstavailable time that the terminal can receive the UL grant message to atime that the terminal actually receives its own radio resourceallocation message (or information) from the base station. Here, theradio resource allocation message is received from the base stationafter the base station successfully decodes the previously transmittedSR. As such, unlike the first and second time period, the terminal mustmonitor and receive the downlink channel during the third time period.

The fourth time period may refer to a time period from the time that theterminal actually receives its own radio resource allocation message toa next available time that the terminal can transmit the SR on the PUCCH(if the previous SR transmission is failed). If the previouslytransmitted SR is not received by the base station, the terminal may notable to receive the radio resource allocation message. In this case, amonitoring of the downlink channel during this time period may be anunnecessary operation.

As described above, during a radio resource allocation procedure, amonitoring operation of the terminal for a downlink channel (e.g.,PUCCH) may not be necessary for a certain time period. Namely, if theterminal continuously monitors the downlink channel for entire timeperiod, it will cause unnecessary battery consumption of the terminal.

Accordingly, the present disclosure may propose an improved radioresource allocation method with high power efficiency. To do this, thepresent disclosure may propose to control a downlink channel monitoringtime by using a timer.

Preferably, after transmitting an SR through a PUCCH, the terminal mayoperate a sleep mode timer, and immediately operates in a continuousreception mode. Then, if the sleep mode timer expires, the terminal maystop the continuous reception mode and may change its operation in adiscontinuous reception mode. If the terminal receives the radioresource allocation from the base station during the operation of thesleep mode timer, the terminal may stop to operate the sleep mode timer.

Preferably, after transmitting an SR through a PUCCH, the terminal mayoperate a sleep stop timer. Thereafter, the terminal may operate in adiscontinuous reception mode or may stop to monitor the downlink channelsuch as the PDCCH. Then, if the sleep stop timer expires, the terminalmay operate in a continuous reception mode, thereby continuouslymonitoring the downlink channel. During the above procedure, as anadditional step, the terminal may operate the sleep mode timer when thesleep stop timer is expired. Then, if the sleep mode timer expires, theterminal may stop to operate the continuous reception, and may changeits operation in a discontinuous reception mode. If the terminalreceives the radio resource allocation from the base station during theoperation of the sleep mode timer, the terminal may stop to operate thesleep mode timer.

Preferably, after requesting a radio resource allocation through a D-SRchannel, if the terminal is in a first discontinuous reception mode(e.g., long DRX), the terminal may change its operation in a seconddiscontinuous reception mode (e.g., short DRX).

During the above procedure, a setup value of the timer may be notifiedto a terminal by a base station. Also, a setup value of the receptionstop timer (or sleep stop timer) may set to a RTT of a HARQ operation.

According to the present disclosure, after the SR is triggered, if acertain condition is satisfied, the terminal may monitor or receive adownlink channel. Also, according to the present disclosure, theterminal may not monitor or receive the downlink channel if the certaincondition is not satisfied. Here, the certain condition may refer to aspecific time or case when the terminal transmits the SR through thePUCCH and/or the transmission of the SR is pending.

FIG. 6 illustrates a radio resource allocation procedure aftertriggering of a BSR and an SR according to an embodiment of the presentinvention.

As shown in the FIG. 6, the radio resource allocation procedure may bedivided into 4 different time period.

The first time period may refer to a time period from a time that a BSR(buffer state report)/SR (scheduling request) is triggered or pending toa first available time that SR can be transmitted on a PUCCH. Ingeneral, the first time period may be varied according to a setup of theradio resource(s) allocation of the PUCCH for transmitting the SRrequest. In the FIG. 5, it is assumed that the PUCCH radio resource(s)are allocated at 0 ms, 20 ms, 40 ms. Here, if the SR is triggered at 2ms, the terminal does not perform any operation from 2 ms to 20 ms,because the SR only can be actually transmitted to the base station at20 ms. As described above, according to the present disclosure, themonitoring operation for a downlink channel is not performed for thisperiod so as to minimize an unnecessary power consumption of theterminal.

The second time period may refer to a time period from a time that theSR is transmitted to a first available time that the terminal canreceive a UL grant message from a base station (e.g., eNB). In general,the second time period may be related to an uplink/downlink RTT and/or aprocessing time by the base station. Accordingly, after transmitting theSR, there is some time delay that the terminal has to wait for receivingthe radio resource allocation message. As described above, according tothe present disclosure, the monitoring operation for a downlink channelis also not performed for this period so as to minimize an unnecessarypower consumption of the terminal.

The third time period may refer to a time period from the firstavailable time that the terminal can receive the UL grant message to atime that the terminal actually receives its own radio resourceallocation message (or information) from the base station. Here, theradio resource allocation message is received from the base stationafter the base station successfully decodes the previously transmittedSR. As such, unlike the first and second time period, according to thepresent disclosure, the terminal performs monitoring operation for thedownlink channel during the third time period.

The fourth time period may refer to a time period from the time that theterminal actually receives its own radio resource allocation message toa next available time that the terminal can transmit the SR on the PUCCH(if the previous SR transmission is failed). According to the presentdisclosure, in order to eliminate the unnecessary power consumption ofthe terminal, the monitoring operation of the terminal is not performedfor this time period.

In the present disclosure, the SR may be used for requesting an uplinkshared channel (e.g., UL-SCH) resources for new transmission. Further,when the SR is triggered, it may be considered as pending until it iscancelled. All pending SR(s) may be cancelled and a scheduling requestprohibit timer may be stopped when a data unit (e.g., MAC PDU) isassembled and this data unit includes a BSR which contains buffer statusup to (including) the last event that triggered BSR, or when the uplinkgrant can accommodate all pending data available for transmission.

The present disclosure may provide a method of controlling a monitoringoperation of a physical downlink channel in wireless communicationsystem, the method comprising: triggering a signaling in order toallocate at least one radio resource for an uplink data transmission;determining whether the triggered signaling is being transmitted to anetwork; and selectively performing the monitoring operation of thephysical downlink channel based on the determining step, wherein themonitoring operation is performed if it is determined that the triggeredsignaling is transmitted to the network, the monitoring operation is notperformed if it is determined that the triggered signaling is nottransmitted to the network, the signaling is transmitted to a networkvia a PUCCH, the signaling is an SR signaling, the physical downlinkchannel is a PDCCH, and the signaling is related to an SR procedure.

Although the present disclosure is described in the context of mobilecommunications, the present disclosure may also be used in any wirelesscommunication systems using mobile devices, such as personal digitalassistants (PDAs) and laptop computers equipped with wirelesscommunication capabilities (i.e. interface). Moreover, the use ofcertain terms to describe the present disclosure is not intended tolimit the scope of the present disclosure to a certain type of wirelesscommunication system. The present disclosure is also applicable to otherwireless communication systems using different air interfaces and/orphysical layers, for example, time division multiple access (TDMA), codedivision multiple access (CDMA), frequency-division multiple access(FDMA), wideband code division multiple access (WCDMA), orthogonalfrequency-division multiplexing (OFDM), Evolution-Data Optimized (EVDO), Worldwide Interoperability for Microwave Access (WiMax), wirelessbroadband (WiBro), etc.

The exemplary embodiments may be implemented as a method, apparatus orarticle of manufacture using standard programming and/or engineeringtechniques to produce software, firmware, hardware, or any combinationthereof. The term “article of manufacture” as used herein refers to codeor logic implemented in hardware logic (e.g., an integrated circuitchip, Field Programmable Gate Array (FPGA), Application SpecificIntegrated Circuit (ASIC), etc.) or a computer readable medium (e.g.,magnetic storage medium (e.g., hard disk drives, floppy disks, tape,etc.), optical storage (Compact Disc Read-Only memory (CD ROMs), opticaldisks, etc.), volatile and non-volatile memory devices (e.g.,Electrically Erasable Programmable Read-Only Memory (EEPROMs), read onlymemory (ROM), random access memory (RAM), programmable read only memory(PROM), static random access memory (SRAM), dynamic random access memory(DRAM), firmware, programmable logic, etc.

Code in the computer readable medium may be accessed and executed by aprocessor. The code in which exemplary embodiments are implemented mayfurther be accessible through a transmission media or from a file serverover a network. In such cases, the article of manufacture in which thecode is implemented may comprise a transmission media, such as a networktransmission line, wireless transmission media, signals propagatingthrough space, radio waves, infrared signals, etc. Of course, thoseskilled in the art will recognize that many modifications may be made tothis configuration without departing from the scope of the presentdisclosure, and that the article of manufacture may comprise anyinformation bearing medium known in the art.

As the present disclosure may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by any of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims, and therefore allchanges and modifications that fall within the metes and bounds of theclaims, or equivalents of such metes and bounds are therefore intendedto be embraced by the appended claims.

What is claimed is:
 1. A method of monitoring a downlink channel in awireless communication system, the method comprising: triggering, by auser equipment (UE), a scheduling request (SR); transmitting, by the UE,the SR to a network after the SR triggering; and monitoring, by the UE,the downlink channel for a certain time, wherein the certain timerelates to a time that the SR is transmitted to the network.
 2. Themethod of claim 1, the SR is used for requesting one or more uplinkresources for an uplink data transmission.
 3. The method of claim 1,wherein the SR is transmitted to the network via a physical uplinkcontrol channel (PUCCH).
 4. The method of claim 1, wherein the downlinkchannel is a physical downlink control channel (PDCCH).
 5. The method ofclaim 1, wherein the downlink channel is continuously monitored while atimer is running.
 6. The method of claim 5, wherein the timer is startedto operate after the transmission of the SR.
 7. The method of claim 5,wherein the downlink channel is no longer monitored when the timerexpires.
 8. The method of claim 1, wherein the downlink channel is nolonger monitored when the one or more uplink resources are allocated onthe downlink channel.
 9. The method of claim 1, wherein the certain timefurther relates to a time that the one or more uplink resources areallocated on the downlink channel.
 10. The method of claim 9, whereinthe certain time is a time between the transmission of the SR and theallocation of the one or more uplink resources on the downlink channel.11. An apparatus for monitoring a downlink channel in a wirelesscommunication system, the apparatus comprising: a processor configuredto trigger a scheduling request (SR), to transmit the SR to a networkafter the SR triggering, and to monitor the downlink channel for acertain time, wherein the certain time relates to a time that the SR istransmitted to the network.
 12. The apparatus of claim 11, the SR isused for requesting one or more uplink resources for an uplink datatransmission.
 13. The apparatus of claim 11, wherein the SR istransmitted to the network via a physical uplink control channel(PUCCH).
 14. The apparatus of claim 11, wherein the downlink channel isa physical downlink control channel (PDCCH).
 15. The apparatus of claim11, wherein the downlink channel is continuously monitored while a timeris running.
 16. The apparatus of claim 15, wherein the timer is startedto operate after the transmission of the SR.
 17. The apparatus of claim15, wherein the downlink channel is no longer monitored when the timerexpires.
 18. The apparatus of claim 11, wherein the downlink channel isno longer monitored when the one or more uplink resources are allocatedon the downlink channel.
 19. The apparatus of claim 11, wherein thecertain time further relates to a time that the one or more uplinkresources are allocated on the downlink channel.
 20. The apparatus ofclaim 19, wherein the certain time is a time between the transmission ofthe SR and the allocation of the one or more uplink resources on thedownlink channel.